Persistence of HIV-1 structural proteins and glycoproteins in lymph nodes of patients under highly active antiretroviral therapy

Here we report a long-term persistence of HIV-1 structural proteins and glycoproteins in germinal centers (GCs) of lymph nodes (LNs) in the absence of detectable virus replication in patients under highly active antiretroviral therapy (HAART). The persistence of viral structural proteins and glycoproteins in GCs was accompanied by specific antibody responses to HIV-1. Seven patients during the chronic phase of HIV-1 infection were analyzed for the presence of the capsid protein (HIV-1p24), matrix protein (HIV-1p17), and envelope glycoproteins (HIV-1gp120/gp41), as well as for viral RNA (vRNA) in biopsy specimens from LNs obtained before initiation of therapy and during HAART that lasted from 5 to 13 months. In parallel, these patients were also monitored for viremia and specific anti-HIV-1 antibody responses to structural proteins and glycoproteins both before and during treatment. Before-therapy viral levels, as determined by RT-PCR, ranged from 3 x 10(3) to 6.3 x 10(5) copies of vRNA per ml, whereas during treatment, vRNA was under detectable levels (<25 copies per ml). The pattern of vRNA detection in peripheral blood was concordant with in situ hybridization results of LN specimens. Before treatment, vRNA associated with follicular dendritic cells (FDCs) was readily detected in GCs of LNs of the patients, whereas during therapy, vRNA was consistently absent in the GCs of LN biopsies of treated patients. In contrast to vRNA hybridization results, viral structural proteins and glycoproteins, evaluated by immunohistochemical staining, were present and persisted in the GC light zone of LNs in abundant amounts not only before initiation of therapy but also during HAART, when no vRNA was detected in GCs. Consistent with immunohistochemical findings, specific antibody responses to HIV-1p17, -p24, and -gp120/gp41, as evaluated by ELISA and virus neutralization, persisted in patients under therapy for up to 13 months of follow-up. The implications of these findings are discussed in relation to HIV-1 persistence in infected individuals and the potential role of chronic antigenic stimulation by the deposited structural proteins in GCs for AIDS-associated B cell malignancies.     

HTLV-I infection of T and B cells of a patient with adult T-cell leukemia-lymphoma (ATLL) and transmission of HTLV-I from B cells to normal T cells

We analysed the DNA of different tissues of a patient (HS) with adult T-cell leukemia/lymphoma virus (HTLV-I). We detected viral sequences in fresh specimens from spleen, thymus, liver, skin and peripheral blood neoplastic lymphocytes. The pattern of HTLV-I intergration is identical in the leukemic cells and in all other tissues analysed, but the signal intensity is strongest in the leukemic cells, indicating the source of HTLV-I proviral sequences was the leukemic T-cells which had infiltrated these tissues. In fact, the cultured skin fibroblasts of the patient did not contain HTLV-I sequence. However, cultured lymphocytes of this patient was consistently an immortalized B-cell line containing HTLV-I sequences in a manner indicative of a polyclonal infection. This cell line was also infected with the Epstein-Barr virus (EBV). In order to determine whether HTLV-I alone was sufficient for B-cell immortalization, we obtained single cell clones by limiting dilution. The DNA of all the cell clones that we analysed contained both the HTLV-I and EBV genomes, suggesting that immortalization of the B-cell was more likely due to the EBV rather than HTLV-I. Infectious HTLV-I viruses produced by the B-cell line still had the propensity to infect and transform T-lymphocytes in normal human umbilical cord blood. Unlike the parental B cells, the transformed T lymphocytes were clonally selected. Our results indicate that although the predominant infected cell population of the patient was his leukemic T lymphocytes, some of his EBV-positive B-lymphocytes were also polyclonally infected. The latter had a growth advantage in culture over the T lymphocytes but the virus produced by these immortalized B cells has not been adapted and has maintained its tropism for T cells.     

Short-term postischemic hypoperfusion improves recovery of protein synthesis in the rat brain cortex

A cell-free system from rat brain cortex was used to follow changes in protein synthesis after ischemia and reperfusion (four-vessel occlusion). The experiment was focused to prevent a violent burst of free oxygen radicals creation during the first period of postischemic reperfusion by short-term hypoperfusion. After 30 min of ischemia, the authors applied hypoperfusion produced by releasing one (right) carotid for the first 5 min of reperfusion lasting from 30 min to 3 d. Results obtained by this procedure show that the activity of protein synthesis machinery from hypoperfused brains is higher than normovolemic ones; the left hemisphere, which is contralateral to direct blood flow during hypoperfusion, shows better results than the right hemisphere.     

Improvement of energy state and basic modifications of neuropathological damage in rabbits as a result of graded postischemic spinal cord reoxygenation

The role of graded postischemic reoxygenation applied at the end of 20 min of spinal cord ischemia was studied with respect to the intraspinal pO2 tension, energy state, and histopathological sequelae. Graded postischemic reoxygenation can induce a positive shift in the intraspinal pO2 tension, but normal postischemic reoxygenation with normotensive pO2 blood tension inevitably causes the postischemic intraspinal pO2 overshoot. Graded postischemic reoxygenation significantly improves the energy state expressed by higher adenosine triphosphate (ATP), phosphocreatine (PCr) and glucose levels. Using the Nauta impregnating degenerating method, clear histopathological differences were found in the L3-S3 segments after 20 min of ischemia. Apparently divergent damage was observed when normal reoxygenation or graded postischemic reoxygenation was used. Diametrically different histopathological outcomes were obtained with normal reoxygenation and graded postischemic reoxygenation 2 and 4 days postoperatively.     

Nalpha-tosyl-L-arginine-p-nitroanilide as substrate in color test and polarographic test of trypsin

A practical procedure is described for a sensitive photometric and polarographic determination of trypsin, using $\text{N}{}^{\mathrm{\alpha }}\text{-}\text{tosyl-}\text{l}\text{-arginine}\text{-p-}\text{nitroanilide}$ (l-TAPA) as substrate. The test is suitable for routine analysis of series of clinical samples. The enzymatic activity is determined from the quantity of p-nitroaniline liberated hydrolytically and established photometrically or polarographically. The polarographic determination is suitable for nonhomogeneous or colored media. The test can be carried out even if the sample concentration of trypsin is lower than 1 μg/ml. A method is presented for calculation of the enzyme units directly from the polarographic wave height of p-nitroaniline liberated enzymatically.     

Blood flow and electrolytes in spinal cord ischemia

The contribution of reoxygenation-reperfusion injury to ischemic brain damage has been clearly demonstrated but not in the spinal cord. To evaluate this phenomenon in spinal cord ischemia, we measured spinal cord blood flow (SCBF) by [14C]iodoantipyrine and electrolytes in rabbits after 10 or 40 min ischemia followed by 30 min or 4 days recirculation. Ischemia for 10 or 40 min reduced blood flow in the lower lumbar segments L5-L7 (30 ml/100 g/min) to 5 and 10% of control. After 30 min of recirculation moderate hyperemia (25-40% above control) was observed in segments L5-L7 which was not related to the degree of functional impairment. Na+, water, and Ca2+ increased and K+ decreased after 40 min ischemia, but were unchanged after 10 min ischemia. Recirculation for 30 min after 40 min of ischemia resulted in a progressive rise in Ca2+ which correlated with irreversible spinal cord injury.     

Employment and aging--a contribution from the viewpoint of social gerontology

Issuing from shift work specific respectively occupation specific characteristics of mortality and morbidity the author refer to a possible context between lifetime occupational activity and special forms of aging. It is out the examination of the postulated context within the bounds of gerontological study of Halberstadt.     

Amelioration of ischemic spinal cord damage by postischemic treatment with propentofylline (HWA 285)

The effect of the xanthine derivative propentofylline (HWA 285) on metabolic and functional recovery in rabbit spinal cord after 20 and 30 min ischemia and 4 days of reperfusion was investigated. Pre-treatment with 20 mg/kg significantly improved recovery of the energy state in the spinal cord, however, without significant functional recovery of hindlimbs. In contrary, post-treatment with HWA 285 recovered the energy state to pre-ischemic value and also significantly improved functional recovery. These findings suggest that the neuroprotective mechanism of HWA 285 in the spinal cord is not associated with inhibition of glutamate release as supposed to operate in the gerbil brain.     

Ischemic Postconditioning and Nitric Oxide Administration Failed to Confer Protective Effects in a Porcine Model of Extracorporeal Cardiopulmonary Resuscitation

The protective effects of ischemic postconditioning (IPC) and nitric oxide (NO) administration have been demonstrated in several ischemic scenarios. However, current evidence regarding the effect of IPC and NO in extracorporeal cardiopulmonary resuscitation remains lacking. Fifteen female swine (body weight 45 kg) underwent veno‐arterial extracorporeal membrane oxygenation (ECMO) implantation; cardiac arrest‐ventricular fibrillation was induced by rapid ventricular pacing. After 20 min of cardiac arrest, blood flow was restored by increasing the ECMO flow rate to 4.5 L/min. The animals (five per group) were then randomly assigned to receive IPC (three cycles of 3 min ischemia and reperfusion), NO (80 ppm via oxygenator), or mild hypothermia (HT; 33.0°C). Cerebral oximetry and aortic blood pressure were monitored continuously. After 90 min of reperfusion, blood samples were drawn for the measurement of troponin I, myoglobin, creatine‐phosphokinase, alanine aminotransferase, neuron‐specific enolase, cystatin C, and reactive oxygen metabolite (ROM) levels. Significantly higher blood pressure and cerebral oxygen saturation values were observed in the HT group compared with the IPC and NO groups (P < 0.05). The levels of troponin I, myoglobin, creatine phosphokinase, and alanine aminotransferase were significantly lower in the HT group (P < 0.05); levels of neuron‐specific enolase, cystatin C, and ROM were not significantly different. IPC and NO were comparable in all monitored parameters. The results of the present study indicate that IPC and NO administration are not superior interventions to HT for the maintenance of blood pressure, cerebral oxygenation, organ protection, and suppression of oxidative stress following extracorporeal cardiopulmonary resuscitation.     

Human T-cell leukemia/lymphoma virus I and/or Epstein-Barr virus-infected B-cell lines spontaneously produce acid-labile α-interferon

B-cell lines were established as spontaneous outgrowths of cell cultures from patients with adult T-cell leukemia (ATL). Three such lines were shown to have integrated human T-cell leukemia/lymphoma virus 1 (HTLV-I) proviral sequences as well as Epstein-Barr virus (EBV) infection. Supernatant fluids from these cultured cells were assayed for interferon (IFN) production. Acid-stable -IFN was found to be produced by one cell line (CF), and acid-labile -IFN by the other two (HS, MJB). In contrast, HTLV-I-infected T-cell lines did not produce IFN. Some EBV-infected B-cell lines produce acid-labile -IFN, while others do not. Since -IFN, both acid stable and acid labile, is found in sera from patients with the polyclonal activation of B cells as a constitutive part of the disease, the above observations suggest a possible role of polyclonal B-cell activation in -IFN production in these diseases.